schonfeld



July 17; 1923.

P. SCHNFELD GRIPPING DEVICE FOR LIFTS AND THE LIKE Filed Aug. 24. 1921 3 Shoa -She "1 P. SCH6NFELD GRIPPING DEVICE FOR LIFTS AND THE LIKE July -17, 1923. 1,462,382

Filed Aug. 24. 1921 3 Sheets-Sheet 5 A IOl 53:6

2/ LL n o o o u o I a Z o i i 0 0 a Y o o 0 i g f i d 7:. e o o 0 \GD 0 o u {0 o I Q o n o Patentedlluly 1?, 1923.

warren stares 1,462,383 PATENT orrlcs.

PAUL'SCHGNFELD, or BOCI-IUM-WEITMAR, GERMANY.

GRIPPING DEVICE FOR LIFTS AND THE LIKE.

Application filed August 24, 1921. Serial No. 4%,962.

T 0 all w 710m it may concern:

Be it known thatI PAUL So HoN FELn a gust 27, 1920), of which the following is a specification.

. My invention relates to gripping devices for cages, lift platforms and the like and its object is to prevent clogging of the teeth of such devices by the chips detached from the guide rails, which is the most frequent cause of failure of such gripping devices.

According to my invention, the chips from the guide rails are conducted to the outside in the same direction in which they have been detached. This is, achieved by forming the teeth of the gripping clutches after the manner of a grid or railing, so that interstices are left between them which communicate with a chamber provided behind the teeth. The cutting teeth so arranged are united by the lateral checks of thechamber. The chips which are detached owing to the engagementof the gripping pawls are discharged to the rear through the interstices. Besides, the teeth may be inclined in order to effect an additional transverse displacement, which, however, is not indispensable. It is also possible to form the teethin the manner of the well known herringbone teeth with advancing or following points. i

In the drawings affixed to the specification and forming part thereof, several devices embodying my invention are illustrated by way of example. In the draw- 1ngs-- Figs. 1 and 8 are elevations showing the toothed faces of the gripping pawls while Fig. 2 is an elevation of the pawls in operative position. I Figs. 4 and 5 illustratea modification of the pawls in inoperative and operative position, respectively, I

Figs. 6 and 7 are sections of partof a cage or the like, on which my improved device is arranged. I

Referring now to Figs. 1 to3, the pawls Z which are adapted to turn on pivots 7c, are provided on their faces with teeth on with slots ,9 between them. The teeth are connected by cheeks t, on either side so that a box like chamber is formed, which the chips detached by the teeth enter, where upon they fall out of the pawls. If, as illustrated, the teeth are arranged atan angle, the teeth above the cheeks if can not be clogged either as here the chips either enter the slots s or are immediately-thrown out. The teeth above the cheeks t might also be cut away up to the cheeks so that they are exposed on their entire effective width. Instead of arranging the teeth between two cheeks, as shown, in smaller devices, only a central rib may be provided, the teeth projecting on either side of said rib.

Obviously by this invention the problem is solved of p-reventing'the clogging of the teeth so that their operation is reliable.

Consequently, the motion of the cage or the like is retarded to a limited extent when the rope breaks. This retarding is effected by a' regular change of form, as by'detaching chips. The chips'are successively removed by the teeth and a planer.

The gripping pawls so constructed performing the work of lifting chips whichis necessary for-producing with suiiicient reliability a'predetermined retarding action, it

is also necessary to safeguard the effective ness of the improved gripping pawls in other respects.

To this end several improvementshad to be made which are illustrated in Figs. 4+7.

Figs. 4 and 5 illustrate the gripping pawls ininoperative and operative position, respectively.

Figs. 6 and 7 are longitudinal sections of the upper portion of a cage showing the means for operating the gripping pawls, and in particular their kinematic relation to the vertical rod (king rod), arranged at the centre of the cage to which the rope is attached. The work of detaching chips necessary for a limited retardation differs according to whether the guide rails are comparatively new or worn With the usual fixed stops of the gripping pawls heretofore used, which are rigidly secured to the cage, the pawls would in the first case perhaps be forced far too much into the wood, and in the second case, toolittle.

The disturbance of the operation of the,

to which the guiderails are worn. This removed to the rear as in provided.

set.

.my invention can be combined which considers the fact that the guide rails must be interrupted at the several levels of the shaft to render the cages easily accessible. Here, it might occur, that the pawls engage oneanother so that they would engage the guide rails at an obtuse angle, after the mouth of the gallery has been passed. In

order to avoid this, rigid stops are pro-' vided in combination with the ball shaped extensions a so that the pawls are prevented from engaging by these stops engaging a guide shoe (Z. Obviously there is normally a clearance between the stops 0 and the guide shoe (Z, as the depth of penetration of the pawls Z is determined by the ball shaped faces a sliding on the guide rails Z).

The arrangement of the guide shoe (Z at the point indicated has also a particular ob- Heretotore, the guide shoes (Z were as a rule arranged above the pawls where the guide rails are worn already by the operation of the gripping devices. As here, however, the guide shoes (Z are below the gripping pawls Z, they will remain per manently efiective as they still engage the portion of the guide rails (Z which is not worn. explained, above, form a ready means for controlling the stops 0 of the gripping pawls Z.

This arrangement also allows to place the pivots ll: of the gripping pawls Z so far apart, that under the action of the pawls there is sufiicient leverage to prevent under all conditions a disengagement of the gripping pawls. Heretofore, the pawls Z were placed so near the guides 6, that the pawls were inclined at a comparatively great angle (Figs. 1 and 2) whereby, the danger was created of the pawls becoming disengaged so that special locking devices had to be The arrangement according to Figs. 4 to 5 permits to avoid this drawback in a different manner.

.There is another cause of obstruction which must be removed. As is well known. the engaging movement of the gripping v pawls is made dependent upon the vertical rod 6, which is under the action of a strongspring f. As long as the spring 7 is com pressed by the weight of the cage and the rope is not broken, the pawls are disengaged. When the rope breaks, spring will expand and cause the gripping pawls Z to engage, which are operatively connected with the rod 6. With the arrangements At the same time the shoes (Z, as

heretofore employed there appeared the phenomenon that the four gripping pawls will not engage the guide rails uniformly, but, for example, only-these pawls will engage the guide rails which are disposed on diagonally opposite sides of the cage, so that the device does not operate correctly.

The cause of this phenomenon is, that the cinematic system composed olthe vertical rod, grioping pawls and connecting rods is a self contained mechanism, that is a mechanism in which a movement of one member causes a definite movement of all other members. Since now the cage is held bv the guide shoes, in a definite position in relation to the guide. rails, it may happen. that it is arrested by the engagement of a single gripping pawl. This is the conse quence of the fact that the self contained mechanism becomes over-self contained. whereby also the part which the several gripping pawls take in the retarding action and the supporting otli the cage becomes statically indefinite. The self contained mechanism is not able to adapt itself to these several conditions of support.

In order to remove this phenomenon which may seriously disturb the operation of the gripping pawls, the self contained mechanism is divided into several mechani" cal systems, all the gripping pawls or at least those pairs of pawls which are disposed. at each front face of a cage, being provided with a separate spring, while the vervical rod only has to release a locking device which maintains the gripping pawls in locked position. Consequently, the gripping pawls will engage on either side without their kinematic dependency exerting a disturlinfluence.

The particular arrangement employed to this end is the following: On the pivots A". of the gripping pawls Z there are disposed levers 71 which are held together by means of a clamp 77. said clamp being acted upon by a spring a. The rod 0 operates the bell crank levers 0, (Fig. 6) which bymeans of connecting rods operate bolts 9. which pass through the'front walls of the cage and get into position in front of the pawls Z. When the rope g breaks and spring 7 expands, the rod e is withdrawn and the bolts 9 are withdrawn also so that the springs a are able to cause the gripping pawls Z to engage. The independence hereby provided in a similar manner as in trip gears for steam engines permits an exact engagement of the gripping pawls on either side. In order to prevent damage to the rods 9) or bolts g, respectively, when the cage is raised again and the spring 7 is compressed, which might occur, as the bolts 7 now abut against the grip ping pawls which are in operative position, v

be bent downwards but yield upwards. All these parts are returned to normal position by moving apart thegripping pawls, which trated in Fig. 6. I

A further difficulty consists therein that all the parts of the system of links move with considerable resistance. In the operation of a mine shaft where there is not sufficient attention and eXamina-tion'paidto the working of such a device, it may easily happen, that the several parts are stuck by rusting, so that they can be moved only with difficulty or not at all. Inorder to avoid this, not

only the bearings of my improved. device are suitably constructed and suitable lubrication is provided, but those parts which are particularly exposed to damage, are protect ed by special means. For example, the guide of the rod e is formed as a chamber u closed on either side by short insertions o and is maintained filled with grease by means of grease boxes w, so that it can not become rusty on the inside and is further provided with lubricant in sufficient quantities. In

the same manner, the springs 'n are con structed in frustoconical shape, and also filled with grease by aid of cups. I claim suitable grease 1. In a gripping device for lifts in combination, a cage, a grip jaw connected with said cage, a wooden rail adapted to be gripped by said j aw and a plurality of super posed cutting teeth on said jaw spaced apart so as to allow chips of wood to pass between them. I a

2. In a gripping device for lifts in combi nation, a cage, a grip jaw substantially Pdshaped in cross-section connected with said cage, a wooden rail adapted to be gripped by said jaw and a plurality of superposed cutting teeth on said jaw spaced apart so to allow chips of wood to pass between them.

posed cutting teeth on said jaw spaced apart I In a gripping device for lifts in combi'- so as to allow chips of wood to pass between them and a smooth cheek formed on the lower portions of said jaw. have engaged the guide rails, by means of a screw or the like, sothatthe bolts q are able to move outwards in the manner illussaid cage, a wooden rail adapted to be gripped by said jaw, a plurality of superposed cutting teeth on said jaw spaced apart so as to allow chips of wood to pass between them and a guide shoe arranged underneath said jaw.

,7. In a gripplng device for lifts in combination, a cage, a grip jaw connected with V said'cage, a wooden rail adapted to be gripped by said jaw, a plurality of superposed cutting'teeth onsaid jaw spaced apart so as to allow chips-of wood to pass between them, means for locking said jaw in inoperav tive position and a king rod on said cage operatively connected with said locking means and adapted to release said jaw.

. 8. In a gripping device for lifts in combination, a cage, a grip jaw connected with said cage, a wooden rail adapted to be gripped by said jaw, a plurality of super-- posed cutting teeth on said jaw spaced apart so as to allow chips of wood to pass between them, a spring tendmg tomove said aw into operative position, means for locking said jaw in inoperative position and a king rod on said cage operatively connected with said locking means and adapted to release said jaw.

9. In a gripping device for lifts in combination, a cage, a grip jaw connected with said cage, a wooden rail adapted to be gripped by said jaw, a plurality of superposed cutting teeth on'said jaw spaced apart so as to allow chips ofwood to pass between them, means for locking said aw in inoperative position and a king rod onsaid cage oper'atively connected with said locking means and adapted to release said jaw, the connection between said rod and said locking means being such that said means are free to move upwards. r

. In testimony whereof I affix mysignature.

PAUL soHoNFELn. 

